The circuit shown in Figure, acts as a ... and for the given inputs, its output voltage is . . . . . $$V.$$

Let the magnitude of the gain in the inverting op - amp amplifier circuit shown be $$x$$ with switch $${S_1}$$ open. When the switch $${S_1}$$ is closed, the magnitude of gain becomes.

A non inverting op - amp amplifier is shown in figure. The o/p voltage is

The common mode voltage of a unity gain (voltage follower) op-amp buffer in terms of its output voltage $${V_0}$$ is __________.